Tatiana Bradley | 7c9dd8d | 2023-08-29 12:16:24 -0400 | [diff] [blame] | 1 | // Copyright 2023 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package proxy |
| 6 | |
| 7 | import ( |
| 8 | "encoding/json" |
| 9 | "net/http" |
| 10 | "net/http/httptest" |
| 11 | "os" |
| 12 | "path/filepath" |
| 13 | "sync" |
| 14 | "testing" |
| 15 | ) |
| 16 | |
| 17 | // NewTestClient creates a new client for testing. |
| 18 | // If update is true, the returned client contacts the real |
| 19 | // proxy and updates the file "testdata/proxy/<TestName>.json" with |
| 20 | // the responses it saw. |
| 21 | // If update is false, the returned client is a fake that |
| 22 | // reads saved responses from "testdata/proxy/<TestName>.json". |
| 23 | func NewTestClient(t *testing.T, update bool) (*Client, error) { |
| 24 | t.Helper() |
| 25 | |
| 26 | fpath := responsesFile(t) |
| 27 | if update { |
| 28 | // Set up a real proxy and register a function to write the responses |
| 29 | // after the test runs. |
| 30 | pc := NewClient(http.DefaultClient, ProxyURL) |
| 31 | t.Cleanup(func() { |
| 32 | if err := os.MkdirAll(filepath.Dir(fpath), os.ModePerm); err != nil { |
| 33 | t.Error(err) |
| 34 | return |
| 35 | } |
| 36 | if err := pc.writeResponses(fpath); err != nil { |
| 37 | t.Error(err) |
| 38 | } |
| 39 | }) |
| 40 | return pc, nil |
| 41 | } |
| 42 | |
| 43 | // Get the fake client from the saved responses. |
| 44 | b, err := os.ReadFile(fpath) |
| 45 | if err != nil { |
| 46 | return nil, err |
| 47 | } |
| 48 | var responses map[string]*response |
| 49 | err = json.Unmarshal(b, &responses) |
| 50 | if err != nil { |
| 51 | return nil, err |
| 52 | } |
| 53 | c, cleanup := fakeClient(responses) |
| 54 | t.Cleanup(cleanup) |
| 55 | |
| 56 | return c, nil |
| 57 | } |
| 58 | |
| 59 | // response is a representation of an HTTP response used to |
| 60 | // facilitate testing. |
| 61 | type response struct { |
| 62 | Body string `json:"body,omitempty"` |
| 63 | StatusCode int `json:"status_code"` |
| 64 | } |
| 65 | |
| 66 | // fakeClient creates a client that returns hard-coded responses. |
| 67 | // endpointsToResponses is a map from proxy endpoints |
| 68 | // (with no server url, and no leading '/'), to their desired responses. |
| 69 | func fakeClient(endpointsToResponses map[string]*response) (c *Client, cleanup func()) { |
| 70 | handler := func(w http.ResponseWriter, r *http.Request) { |
| 71 | for endpoint, response := range endpointsToResponses { |
| 72 | if r.Method == http.MethodGet && |
| 73 | r.URL.Path == "/"+endpoint { |
| 74 | if response.StatusCode == http.StatusOK { |
| 75 | _, _ = w.Write([]byte(response.Body)) |
| 76 | } else { |
| 77 | w.WriteHeader(response.StatusCode) |
| 78 | } |
| 79 | return |
| 80 | } |
| 81 | } |
| 82 | w.WriteHeader(http.StatusBadRequest) |
| 83 | } |
| 84 | s := httptest.NewServer(http.HandlerFunc(handler)) |
| 85 | return NewClient(s.Client(), s.URL), func() { s.Close() } |
| 86 | } |
| 87 | |
| 88 | func responsesFile(t *testing.T) string { |
| 89 | return filepath.Join("testdata", "proxy", t.Name()+".json") |
| 90 | } |
| 91 | |
| 92 | // responses returns a map from endpoints to the latest response received for each endpoint. |
| 93 | // |
| 94 | // Intended for testing: the output can be passed to NewTestClient to create a fake client |
| 95 | // that returns the same responses. |
| 96 | func (c *Client) responses() map[string]*response { |
| 97 | m := make(map[string]*response) |
| 98 | for key, status := range c.errLog.getData() { |
| 99 | m[key] = &response{StatusCode: status} |
| 100 | } |
| 101 | for key, b := range c.cache.getData() { |
| 102 | m[key] = &response{Body: string(b), StatusCode: http.StatusOK} |
| 103 | } |
| 104 | return m |
| 105 | } |
| 106 | |
| 107 | func (pc *Client) writeResponses(filepath string) error { |
| 108 | responses, err := json.MarshalIndent(pc.responses(), "", "\t") |
| 109 | if err != nil { |
| 110 | return err |
| 111 | } |
| 112 | return os.WriteFile(filepath, responses, 0644) |
| 113 | } |
| 114 | |
| 115 | // An in-memory store of the errors seen so far. |
| 116 | // Used by the responses() function, for testing. |
| 117 | type errLog struct { |
| 118 | data map[string]int |
| 119 | mu sync.Mutex |
| 120 | } |
| 121 | |
| 122 | func newErrLog() *errLog { |
| 123 | return &errLog{data: make(map[string]int)} |
| 124 | } |
| 125 | |
| 126 | func (e *errLog) set(key string, status int) { |
| 127 | e.mu.Lock() |
| 128 | defer e.mu.Unlock() |
| 129 | |
| 130 | e.data[key] = status |
| 131 | } |
| 132 | |
| 133 | func (e *errLog) getData() map[string]int { |
| 134 | e.mu.Lock() |
| 135 | defer e.mu.Unlock() |
| 136 | |
| 137 | return e.data |
| 138 | } |